rendering: formalize legacy shader pass fallback

engine/include/XCEngine/Rendering/Builtin/BuiltinPassMetadataUtils.h

@@ -79,6 +79,16 @@ inline bool ShaderPassHasExplicitBuiltinMetadata(const Resources::ShaderPass& sh
     return false;
 }
 
+inline bool ShaderHasExplicitBuiltinMetadata(const Resources::Shader& shader) {
+    for (const Resources::ShaderPass& shaderPass : shader.GetPasses()) {
+        if (ShaderPassHasExplicitBuiltinMetadata(shaderPass)) {
+            return true;
+        }
+    }
+
+    return false;
+}
+
 inline bool ShaderPassMatchesBuiltinPass(
     const Resources::ShaderPass& shaderPass,
     BuiltinMaterialPass pass) {

engine/include/XCEngine/Rendering/Materials/RenderMaterialResolve.h

@@ -409,43 +409,72 @@ inline bool IsTransparentRenderQueue(Core::int32 renderQueue) {
     return renderQueue >= static_cast<Core::int32>(Resources::MaterialRenderQueue::Transparent);
 }
 
-inline bool MatchesBuiltinPass(const Resources::Material* material, BuiltinMaterialPass pass) {
+inline bool HasLegacyMaterialBuiltinPassHints(const Resources::Material* material) {
     if (material == nullptr) {
-        return pass == BuiltinMaterialPass::ForwardLit;
+        return false;
+    }
+
+    return !NormalizeBuiltinPassMetadataValue(material->GetShaderPass()).Empty() ||
+           !NormalizeBuiltinPassMetadataValue(material->GetTag("LightMode")).Empty();
+}
+
+inline bool LegacyMaterialBuiltinPassHintsMatch(
+    const Resources::Material* material,
+    BuiltinMaterialPass pass) {
+    if (material == nullptr) {
+        return false;
     }
 
     const Containers::String shaderPass = material->GetShaderPass();
     const Containers::String lightMode = material->GetTag("LightMode");
     const bool hasMaterialShaderPass = !NormalizeBuiltinPassMetadataValue(shaderPass).Empty();
     const bool hasMaterialLightMode = !NormalizeBuiltinPassMetadataValue(lightMode).Empty();
-    if (hasMaterialShaderPass || hasMaterialLightMode) {
-        if (hasMaterialShaderPass &&
-            !MatchesBuiltinPassName(shaderPass, pass)) {
-            return false;
-        }
-        if (hasMaterialLightMode &&
-            !MatchesBuiltinPassName(lightMode, pass)) {
-            return false;
-        }
+    if (!hasMaterialShaderPass && !hasMaterialLightMode) {
+        return false;
+    }
+
+    if (hasMaterialShaderPass &&
+        !MatchesBuiltinPassName(shaderPass, pass)) {
+        return false;
+    }
+
+    if (hasMaterialLightMode &&
+        !MatchesBuiltinPassName(lightMode, pass)) {
+        return false;
+    }
+
+    return true;
+}
+
+inline bool CanUseLegacyMaterialPassFallback(const Resources::Material* material) {
+    if (material == nullptr) {
         return true;
     }
 
+    const Resources::Shader* shader = material->GetShader();
+    return shader == nullptr || !ShaderHasExplicitBuiltinMetadata(*shader);
+}
+
+inline bool MatchesBuiltinPass(const Resources::Material* material, BuiltinMaterialPass pass) {
+    if (material == nullptr) {
+        return pass == BuiltinMaterialPass::ForwardLit;
+    }
+
     const Resources::Shader* shader = material->GetShader();
     if (shader != nullptr) {
-        bool shaderHasExplicitBuiltinMetadata = false;
         for (const Resources::ShaderPass& shaderPassEntry : shader->GetPasses()) {
             if (ShaderPassMatchesBuiltinPass(shaderPassEntry, pass)) {
                 return true;
             }
-
-            if (ShaderPassHasExplicitBuiltinMetadata(shaderPassEntry)) {
-                shaderHasExplicitBuiltinMetadata = true;
-            }
         }
+    }
 
-        if (shaderHasExplicitBuiltinMetadata) {
-            return false;
-        }
+    if (!CanUseLegacyMaterialPassFallback(material)) {
+        return false;
+    }
+
+    if (HasLegacyMaterialBuiltinPassHints(material)) {
+        return LegacyMaterialBuiltinPassHintsMatch(material, pass);
     }
 
     return pass == BuiltinMaterialPass::ForwardLit;